Methods and apparatus for aggregating MIP and AAA messages

ABSTRACT

Aggregated signaling methods and apparatus which can be used to support the aggregation of Mobile IP binding registration information corresponding to multiple forwarding tunnels are described. Aggregated binding update message are used to enable multiple home addresses from one or more home agents to be installed, refreshed and deleted using a single MIP signaling phase. The single MIP signaling phase may correspond to a single MIP binding update message. Aggregated message techniques can also be used to retrieve multiple home address specific policy profiles via AAA signaling thereby reducing the number of AAA messages required to retrieve AAA information, e.g., profiles, corresponding to multiple home addresses.

RELATED APPLICATIONS

[0001] The present application claims the benefit of U.S. ProvisionalPatent Application S. No. 60/378,404 filed May 7, 2002 entitled:“COMMUNICATIONS METHODS AND APPARATUS” and is a continuation-in-part ofU.S. patent application Ser. No. 10/357,265 filed Feb. 3, 3003 entitled:“A METHOD FOR EXTENDING MOBILE IP AND AAA TO ENABLE INTEGRATED SUPPORTFOR LOCAL ACCESS AND ROAMING ACCESS CONNECTIVITY” which claims thebenefit of U.S. Provisional Patent Application S. No. 60/354,195 filedFeb. 4, 2002 entitled: “A METHOD FOR EXTENDING MOBILE IP TO ENABLEINTEGRATED SUPPORT FOR LOCAL ACCESS AND ROAMING ACCESS CONNECTIVITY”,each of the preceding applications are expressly incorporated byreference into the present application.

FIELD OF THE INVENTION

[0002] The present invention is directed to methods and apparatus forsupporting mobile communications and, more specifically, to methods andapparatus for using aggregated binding update messages and aggregatedauthentication, authorization and/or accounting messages to reducemessage signaling in a mobile communications system.

BACKGROUND

[0003] Mobile IP (IETF RFC2002) enables a moving Internet host toconnect to a Foreign Agent (FA) access router in a foreign network, yetstill be contactable on its persistent Host Home Address (HoA) that ituses on its home network and is likely included in the DNS (Domain NameServer) system. This is possible because the FA gives the host atemporary local address that is either unique to the host e.g., aCo-located Care of Address (CCoA), or is unique to the FA, e.g., a Careof Address (CoA). In an exemplary scenario, the FA registers its CoAinto the Home Agent (HA) for the HoA address of its attached Mobile Node(MN) which corresponds to a user, e.g., a Caller. The HA then tunnelspackets addressed to HoA of Caller to the Care of Address (CoA) of theFA. The FA forwards packets received from the MN HoA out to the Internetas normal. The Caller needs a Security Association (SA) with the HA andthe FA, whilst the FA has a Security Association with the HA, to allowthe signaling to be authenticated and potentially encrypted.

[0004] During a hand-off, the new FA changes the binding in the HA forthe HoA to now map to the new CoA of the new FA. Complexity and problemsarise when multiple network regions are involved in a hand-off, e.g.,because an end node is outside its home network region requiring signalsto be communicated from one region to another so that a mobile node'sHome Agent can be informed of the information, e.g., addressinformation, needed to reach the mobile node in the foreign networkregion. For policy and other reasons local and remote network access maybe handled differently particularly when a mobile node is in a foreignregion. The need, in many cases, to treat local and remote packetforwarding operations differently further complicates matters in regardto updating of forwarding information included in various network nodes.

[0005]FIG. 1 shows prior art MIP signaling between a first node 140 anda second node 150. A MIP Registration Request/Binding Update (RREQ/BU)message 180 is sent between the first node 140 and the second node 150to install a binding in the second node that contains a mapping betweenthe home address of an end node and the Care of Address of that endnode. The home address is allocated to the end node out of an addressprefix assigned to a home agent of the end node. The registrationenables the second node 150/first node 140 to redirect packets addressedto the home address of the end node, between the second node 150/firstnode 140 and the first node 140/second node 150 as indicated bybi-directional IP packet flows for HoA1 182. The registration requestmessage 180 has a MIP Registration Response/Binding UpdateAcknowledgement (RREP/BUack) message 181 which confirms that the bindinghas been installed and reports the nature of any errors. Messages 180and 181 are specific to the Home address 1 (HoA1) of the end node fromthe home agent 1 (HA1) to be mapped to the CoA of the end node.Therefore, a different RREQ/BU message 184 and a different RREP/BUackmessage 185 are required to install the binding for home address 2(HoA2) of the end node from home agent 1 (HA1) to be mapped to the CoAof the end node, so creating bi-directional IP packet flows for HoA2 186between first node 140 and second node 150. Similarly, a RREQ/BUmessages 187 and a RREP/BUack message 188 are required to install thebinding for home address 3 (HoA3) of the end node from home agent 2(HA2) to be mapped to the CoA of the end node, so creatingbi-directional IP packet flows for HoA3 189 between first node 140 andsecond node 150. The first node 140 may be any of an end node, an accessnode containing a MIP agent such as a foreign agent or attendant, whilstthe second node 150 can be an access node containing a MIP agent such asa foreign agent or attendant, or it may be a MIP home agent. It may beseen from FIG. 1 that when the end node has multiple home addresses thata significant amount of signaling is required to install and manage thebindings for an end node, especially during hand-off between accessnodes.

[0006]FIG. 3 shows detailed contents 380 of a prior art MIP registrationmessage 380, such as, for example message 180 or message 181 of FIG. 1.Message 380 includes a home agent address (HA1) 381, a single homeaddress 1 (HoA1) 382 with a first prefix 382 a that is allocated to androutable through the home agent using address 381. The message furtherincludes a CoA of the end node 383 which is mapped with the home address382 in a MIP binding. Finally, the prior art message includes MIPsignaling fields 384 that contains additional signaling information suchas flags, sequence numbers, security and prior art MIP extension fieldsetc used for correct operation of the signaling instance and to describethe type of processing and forwarding to be established for the bindingbetween the home address 382 and the CoA 383 in a MIP mobility agentsuch as a home or foreign agent. Note that during an initialregistration phase, the home address and home agent addresses may beundefined to indicate that the AAA system should dynamically allocate ahome agent to the end node, and the AAA system or home agent shouldallocate a home address to the end node from a prefix at that homeagent. Known MIP registration message do not include more than a singleHoA.

[0007] For the purposes of the description, an address is associatedwith an address prefix of N bit length if that N Most Significant Bitsof the prefix and that address are the same. In addition, whilst asingle MIP signaling instance is already able to manage the allocationof multiple home addresses from a single Home Agent, this is onlypossible if those addresses are defined as a single subprefix of lengthM bits out of an N bit prefix managed by the Home Agent (where N<=M).Non-congruent addresses cannot be supported and specifically a singleMIP signaling instance cannot manage home addresses from different HomeAgent prefixes, nor in fact from different prefixes at different HomeAgents.

[0008] Therefore, existing Mobile IP (MIP) does not provide efficientsupport for multiple Home addresses, to support say both remote andlocal models concurrently via the use of two different Home addresses sothat, e.g., a user can roam the Internet through the use of local accesswhile in a foreign network region and also get corporate/home access atthe same time via the use of remote access to the user's home networkregion. The need for this kind of duality has been seen previously, forexample, on DSL Digital Subscriber Line access networks, so therequirement is not new. For example, a user might wish for eithercomponent to be started or dropped at any time and with full policycontrol by both the foreign and home operators as to what is allowed.The MN could then use an address (HoA) associated with the particularmobile which corresponds to the mobile's Home Agent node, an address(RoA) associated with the particular mobile that corresponds to themobile's Regional Agent (RA) node in combination with packet sourceaddress information to select on a flow by flow basis to route packetsand hence control connectivity features (location visibility, identityvisibility and routing policy) for each users IP ‘session’independently.

[0009] In order to support different routing and treatment for differentIP sessions or applications, e.g., corresponding to remote and localaccess, running on a mobile node, it may be necessary to run multipleinstances of MIP on the mobie resulting in multiple HoA's being assignedto the same mobile and, using existing signaling, requiring at least oneMIP registration message for each HoA corresponding to a mobile. Thishas the unfortunate effect of resulting in multiple MIP registrationupdate messages having to be sent by a mobile, e.g., one per HoA or RoAbeing used, when a hand-off occurs. Multiple MIP registration messagescan have the unfortunate consequence of consuming bandwidth andsignaling resources that might otherwise be used.

[0010]FIG. 5 shows a prior art binding table 580 in a mobility agent. Aseparate MIP signaling instance, e.g., MIP registration request messageand reply, is used to update or create a single entry in the bindingtable 580. The table 580 has entries for a multitude of end nodes suchas Mobile Node X 581 and Mobile Node Y 582. In the case of MN X whichhas three home addresses HoA1 587, HoA2 591 and HoA 3 595, the prior artsignaling creates a binding entry for each MIP signaling instance andhence for each HA/HoA address pair. Entry 583 contains HA1 586, HoA1587, MN X CoA 588 and MIP signaling state 589 associated with thatsignaling instance. Entry 584 contains HA1 590, HoA2 591, MN X CoA 592and MIP signaling state 593 associated with that signaling instance.Thus, for each HA, HoA pair, there is a separate entry 583, 584, 585resulting in similar information being stored multiple times in thememory used to implement the binding table. Entry 585 contains HA2 594,HoA3 595, MN X CoA 596 and MIP signaling state 597 associated with thatsignaling instance. It is clear that CoAs 588, 592 and 596 have the samevalue, that being the CoA of the MN X, and HAs 586 and 590 contains thesame HA address. Further, if the forwarding and security requirements,of the MN X, is the same for each binding entry, then the signalingstate 589, 593 and 597 is highly correlated and can be exactly the samethrough appropriate use of common lifetimes, security associations andsequence numbers. Therefore there is the potential for large amounts ofredundancy in the stored state that implies inefficient storage andassociated messaging.

[0011]FIG. 7 shows prior art AAA signaling between an access node 740and a AAA server 750 that is triggered by the arrival of a connectmessage such as a MIP Registration message at the access node 740. TheAAA signaling is used to authenticate an end node for connection to theaccess node 740, and to authorize a set of communications services forthe end node at that access node 740, and potentially a plurality ofadditional access nodes, as defined by an end node profile associatedwith the home address of an end node. The end node profile is stored inthe access node 740 and used to configure and policy communicationfacilities at that access node 740. A AAA request message 760 is sentfrom access node 740 to AAA server 750 and contains the end nodeidentity such as a MN X Network Access Identifier (NAI) 761 which alsoused to route the AAA request to the home AAA server of the end node.The message 760 will also contain MIP AAA request state used to requestdynamic allocation of HA, HoA and security associations for the MIPservice. The AAA request message 760 may also contain HA1 address 763and HoA1 address 764 if the MN X has multiple profiles, each associatedwith a specific HA/HoA pair. HA1 address 763 and HoA1 address 764 canalternatively contain requirements on the AAA server for the dynamicallocation of a HA1 and/or a HoA1, such as address types and location toensure the appropriate connectivity and communications facilities becomeavailable to the MN X. A AAA response message 770 will then contain theMN X identity NAI 761 to ensure that the returned state is installed forthe correct MN X. Dynamically assigned HA1 address 772 and HoA1 address773 will also be returned but may, especially in the case of staticallyallocated HA and HoA addresses, be returned in the MN X profile for HoA1775, along with the configuration and other policy state. Finally, themessage 770 will typically include other MIP AAA response state 774 suchas dynamically allocated security associations. Now when MN X hasmultiple HoAs 1, 2 and even 3, then the address are from differentaddress prefixes (same or different Home agents) and therefore representdifferent connectivity and hence reachability for communciationsservices, which is essentially the motivation for a MN X having suchmultiple Home addresses. HoA1 might be from a public Internet serviceprovider whilst HoA 2 might be from a corporate network connected to thesame network operator, and hence potentially reachable via a common Homeagent HA1. HoA3 in contrast might be from a third party content providerthat is not part of the common network operator for HoA1/2 and hence isreachable via a second Home agent HA2. In these cases, it is clear thatdifferent reachability is likely to be associated with different MN Xprofiles for each HoA. Therefore, the prior art AAA signaling willrequire additional AAA Request message 780 and AAA Response message 781to fetch the dynamic configuration and MN X profile for HoA2 , and athird set of messages 782 and 783 to fetch the state for HoA3. Clearly,if the AAA server is common for all three AAA signaling instances, andpart of the MN X profile state is common to more than a single HoA, thenthis approach is inefficient in storage and signaling bandwidth.

[0012] In light of the above discussion, it is clear that a better andmore efficient method with supporting apparatus is needed to provideefficient support for multiple Home Addresses in MIP signaling.

SUMMARY OF THE INVENTION

[0013] In accordance with the invention, mobile node functionality isenhanced by supporting multiple parallel instances of MIP in a singlemobile node. This allows local and remote access to be treateddifferently allowing for greater flexibility in network system policy,accounting, security and other issues that arise when a mobile nodeoperates in a visited network region, e.g., foreign domain. While in avisited region, e.g., a foreign domain, local access refers to accesswithin the visited region or domain. This may involve sending packetsto, or receiving packets from, another end node located in the visitednetwork region. Remote access may involve a mobile node in a visitednetwork region accessing or exchanging packets with one or more nodes inthe mobile node's home network region. In accordance with the presentinvention, this can be accomplished by running a separate instance ofMIP in the mobile to deal with remote access separately from localaccess.

[0014] Thus, in accordance with the invention a mobile node may runparallel instances of MIP, one for each Home address. One instance usedfor local access may use a local HA (Home Agent) and HoA (Home Address),e.g., HA1 and HoA1. Remote Access may be supported via another, e.g.,remote HA and a remote HoA, e.g., HA2 and HoA2. This gives the mobilenode independent control of each MIP instance and its particularstandard MIP features such as reverse tunneling, broadcasting etc, andcan select between the two instances on a per IP session basis usingsource address selection. The distinct connectivity planes are bothexposed to the local operator who can now manage and account bothservices. Either plane can be dropped and added as desired although adegree of persistence in the local configuration is desirable to avoidthrashing the AAA system and MIP signalling plane.

[0015] However, without various signaling improvements to MIP which aretaught in the present application, the problems with this model can besevere in terms of the amount of MIP signaling which may occur,particularly as the number of parallel instances of MIP on individualmobile devices increases.

[0016] Absent various features of the invention, ultiple, e.g.,independent, parallel MIP instances in the mobile naturally implies atleast double the signaling, hand-off processing, security associationsand management load due to two or more independent MIP instances,particularly where there is no or only partial integration of the AAA(Authentication, Authorization and Accounting) data for each instance.The more HoAs a MN has then the worse the hand-off overhead andcomplexity becomes.

[0017] Using separate MIP signals as opposed to aggregated signals, eachHoA specific hand-off may complete at significantly different times (outof phase) with each other and the local HA hand-off due to the differenthand-off paths resulting in complex FA and MN state management. Normallylocal hand-off signaling can be completed before remote region hand-offsignaling completes due to shorter path lengths relative to the mobilenode and the network nodes which are updated. This can result in slowhand-off and chained FAs out of step with the local hand-off. A regionalmobility agent can be deployed locally, e.g., in the visited region, inaccordance with one feature or the invention provide the necessarylocalization for the remote access MIP hand-off.

[0018] Some ways of addressing some of the problems discussed aboveassociated with multiple Home Addresses in MIP signaling, in accordancewith various features of the invention, include:

[0019] a) A single phase of AAA exchanges through the foreign and homeAAA servers that is used to configure both local and remote serviceoptions in parallel by returning a composite service profile coveringboth local and remote access, along with any dynamic IP addresses andsecurity associations for HA, RN, HoA and RoA, where the HoA is anaddress associated with the specific MN at the HA and the RoA is anaddress associated with the specific mobile at the RN. For purpose ofexplaining the invention, a Regional Node (RN) is a node which operatesas a regional mobility agent in a visited region. An RN may beimplemented as an HA in a visited region but is described herein as anRA to distinguish from a node's HA in its home domain. A Gateway ForeignAgent is an example of a known RN. Notably, the RoA and HoA correspondto the same mobile node and are not shared with other mobile nodesallowing the RoA and HoA addresses to be mapped to a specific mobilenode and serve as a mobile node identifier.

[0020] b) A single phase of MIP hand-off signalling can be used inaccordance with the invention between the MN and FA, and between the newand old FAs to hand-off traffic to the newFA. This would signal the newCoA for multiple, e.g., all the HoAs of a MN and install standardinter-FA forwarding. This would enable the MN and the FAs to share thesame Security Associations (SAs) for all the HoAs of a MN. Each oldFA(oFA) would store the last MIP reg sent to each HA and would CT (ContextTransfer) these to the newFA (nFA) on hand-off. The newFA would then beresponsible for issuing the proxy parallel MIP registrations tomultiple, e.g, all, the HAs, secured by the nFA-HA and oFA-HA SA. Eachsuch registration may and normally does include the old CoA and newCoAinfo and the present binding information at the HA to be updated to thenewCoA. The nFA may, and often is, also responsible for clearing up ifthe MN hands-off again before the remote access MIP registration, forthe HA/HoA, is completed towards that newFA.

[0021] In accordance with the invention various novel aggregatedmessages are used to manage Mobile IP bindings for multiple homeaddresses of an end node. This reduces signaling requirements ascompared to using multiple conventional MIP messages to perform the sameor similar functions. Aggregated messages of the present invention, incontrast to convention MIP messages, carry multiple home addresses fromthe same home agent. These aggregated messages can be used between theend node and the home agent, between the end node and the foreign agent,between the foreign agent and the home agent and between two foreignagents during a hand-off. The invention is further directed toaggregated messages that enable bindings to be updated in a foreignagent for multiple home addresses that originate from different homeagents. Novel aggregated AAA messages are also supported.

[0022] The invention is also directed to methods and apparatus for usingand processing the novel messages of the present invention. The novelmethods include a message de-aggregation, e.g., fan-out process, thatmay be implemented in the foreign agent that enables different messagesto be generated and sent to multiple home agents as a result of a singleaggregated message from an end node received at the foreign agent. Thereceived aggregated message will normally include home addresses from,e.g., corresponding to, multiple different home agents which provide amobility service to the mobile with which the aggregated message isassociated. In support of the invention, and to reduce binding tablerequirements in various nodes, a novel aggregated binding tablestructure is also supported. In addition to reducing memoryrequirements, the aggregated binding table structure of the presentinvention is well suited for being updated by the aggregated MIPregistration messages of the present invention.

[0023] The invention further provides aggregated messages between theforeign agent and the AAA server that can be triggered by an aggregatedmessage from an end node to be used to fetch multiple home addressspecific end node profiles from the AAA server. Thus, novel aggregatedauthentication, authorization and/or accounting messages are alsosupported. Novel aggregated AAA messages normally included multiple HoAscorresponding to the same mobile node. The aggregated accountingmessages reduce signaling overhead while enabling the end node torapidly configure policy and connectivity for multiple home addresses inparallel. Use of a single aggregated message also operates to ensurethat the AAA system receives requests and/or information correspondingto a hand-off together thereby avoiding problems from receivinginformation associated with a hand-off in different messages, some ofwhich may be delayed or lost resulting in the potential for incompleteor inconsistent processing relating to a hand-off by the AAA system. Thenovel aggregated AAA message can also be used between foreign agents, aspart of a hand-off, to transfer policy state between the old and newforeign agents for the multitude of home addresses employed by an endnode.

[0024] Various other features of the present invention are directed to aHoA list extension that is used to indicate the additional HoAs that areassociated with a master HA/HoA pair included in an aggregated signalingmessage. Further, a HA/HoA list extension is defined and supported. TheHA/HoA list extension is used to indicate one or more additional HoAs atone or more alternative HAs which differ from the master HA of asignaling message. Both extensions may use INCLUDE/EXCLUDE flags toindicate whether the HA/HoA identified in the extension entry is to beinstalled (refreshed) or not refreshed (deleted). Thus, updates to abinding table may be applied selectively to HA/HoA information listed inthe binding table. Thus, use of an aggregated registration message ofthe present invention does not necessarily result in updating of allbinding entries corresponding to HA and/or HoA addresses included in theaggregated message of the invention.

[0025] Various additional features and benefits of the present inventionwill be apparent in view of the detailed description which follows.

DESCRIPTION OF FIGURES

[0026]FIG. 1 shows three prior art MIP signaling instances between afirst node and a second to manage the bindings for three separate Homeaddresses.

[0027]FIG. 2 shows a single aggregated MIP signaling instance of theinvention, between the first node and the second node, for managing thebindings for three Home Addresses at the same time.

[0028]FIG. 3 shows the details of a prior art registration message usedto manage the binding for a single home address.

[0029]FIG. 4 shows registration message details of an exemplaryaggregated message of the invention used to manage the bindings forthree home addresses at the same time.

[0030]FIG. 5 shows the contents of a prior art binding table in amobility agent, such as a foreign or home agent, for managing three homeaddresses.

[0031]FIG. 6 shows the contents of an aggregated binding table entry ofthe invention for managing three home addresses.

[0032]FIG. 7 shows three prior art AAA signaling instances between anaccess node and a AAA server for obtaining the end node profilesassociated with three home addresses.

[0033]FIG. 8 shows a single aggregated AAA signaling instance of theinvention used to obtain three end node profiles at the same time.

[0034]FIG. 9 illustrates an exemplary aggregated message which can beused as an aggregated authentication, authorization and/or accountingrequest message in accordance with the invention.

[0035]FIG. 10 illustrates and exemplary aggregated reply message whichmay be returned in response to the messages of FIG. 9 or FIG. 12.

[0036]FIG. 11 shows an exemplary communications system for using theinvention for registering and handing off multiple home addresses with asingle MIP signaling instance.

[0037]FIG. 12 illustrates an alternative exemplary aggregated messagewhich can be used as an aggregated authentication, authorization andaccounting message in accordance with the invention.

DETAILED DESCRIPTION

[0038]FIG. 2 shows the passing of aggregated messages between first andsecond nodes 240, 250 in accordance with the invention. Node 240includes memory 241 which is part of an interface used to bufferincoming and outgoing messages and data. Similarly, node 250 includesmemory 242 which is part of an interface which buffers messages receivedby or transmitted from node 250. FIG. 4 illustrates an exemplary messagewhich may be communicated between nodes 240, 250 while FIGS. 9 and 11illustrate various exemplary nodes which may be used as the first andsecond nodes 240, 250. The first node 240 may be an end node, such asend node 910, or an access node such as access node 930 of FIG. 11. Thesecond node 240 may be, e.g., a home agent 930 or an access node such asaccess node 920. The registration signaling corresponds to an aggregatedMIP signaling instance, e.g., registration message and correspondingreply message, in accordance with the present invention that is used toefficiently manage multiple bindings for a first end node 240. A singleaggregated MIP registration request or binding update message 280 issent from a first node 240 (similar to first node 140 of FIG. 1) to asecond node 250 (similar to second node 150 of FIG. 1), carryingsufficient information to install multiple bindings in the second node250 for multiple home addresses associated potentially with multiplehome agents, which map to the same CoA of the end node. An aggregatedMIP Registration Response or Binding Update Acknowledgement message 281then reports the result of the binding installation for each of the homeaddresses of the end node back to the first node 240. The use of asingle signaling instance to update registration informationcorresponding to multiple HoAs, made possible by the use of aggregatedmessages, enables the amount of signaling bandwidth and signaling stateto be reduced as compared to using conventional MIP messages. Threebidirectional IP packets flows, represented as dashed line 282, arerouted based on information included in the aggregated signals 280, 281which are used to install bindings into the second node 250 for thethree home addresses HoA1, HoA2 and HoA3 of the first end node 240.

[0039]FIG. 4 shows detailed contents 480 of an exemplary aggregatedregistration message, such as, for example, message 280 or 281 of FIG.2, in accordance with the present invention. Aggregated message contents480 includes a home agent address (HA1) 481 which identifies a node 930(see FIG. 11), a home address 1 (HoA1) 482 with a first prefix 482 aassigned to the identified node 930, a CoA 483 associated with thesecond address 482 and MIP signaling fields 484. In addition, themessage contents 480 includes a second home address (HoA2) 485 with asecond prefix 485 a, said second prefix 485 a being different from saidfirst prefix 482 and being from the first home agent identified byaddress 481. Alternatively or additionally, the message contents 480includes a third home address (HoA3) 487 with a third prefix 487 a wheresaid third prefix 487 a is from the second home agent address (HoA2)486. The aggregated message may include any number N of HoAs where N isequal to at least 2. The contents 480 of the message are arranged sothat the receiving node can uniquely determine the pair comprising theHome agent address and the home address at that home agent that ismapped to the common CoA 483. Therefore, the aggregated message 480 candescribe multiple home addresses from a single home agent, multiple homeaddresses from different home agents as well as additional combinationsof home and home agent addresses. In an exemplary embodiment, theaggregate message would use the pair HA1 481+HoA1 482 as the masterbinding, whilst a MIP extension is used to describe an INCLUDE/EXCLUDElist of additional HoAs at the master HA, followed by a additionalHA+HoA pairs not at the master HA. The include/exclude list structureindicates that the included address pairs should be included or excluded(as indicated by flags) from the binding table entries associated withthis end node CoA as indicated by the include/exclude list. Theinclude/exclude structure provides additional aggregation advantages ascompared to a message without such a list especially as the number ofaddress pairs grows large. The MIP signaling fields 484 in theaggregated message maybe unchanged from that of the prior art messageonly when all address pairs use the same signaling fields. When addresspairs have different forwarding requirements then additional addresspair specific signaling state 488 is appended to the signaling state forthe individual address pairs. Thus, different signaling state 488 may beincluded for the first address pair HA1/HoA1, second address pairHA1/HoA2 and third address pair HA2/HoA3. MIP flags which are the samefor all pairs included in the message 480 may occur only once in themessage, e.g., as part of the set of common MIP signaling fields 484.

[0040] In response to receiving an aggregated binding message, e.g.,message 250, the receiving node will update its binding table entries,e.g., a single aggregated binding table entry will be updated inresponse to receiving an aggregated update message 250. As shown in FIG.6, the single binding table entry may include multiple HAs and HoAs. Aspart of the receiving and updating process, the aggregated message 250may and often is, temporarily stored in memory included in the receivingnode.

[0041]FIG. 6 shows an aggregated binding table structure 680 inaccordance with the present invention, showing entries 681 and 682 forMN X and MN Y. MN X has three home addresses HoA1 482 from HA 1 481,HoA2 486 also from HA1 481 and HoA3 487 from HA2 486. A binding table ofthe type illustrated in FIG. 6 may be used in each of the nodes 920,930, 950-shown in FIG. 9 and may be implemented in memory included inthe node 920, 930, 950 in which the table is located. These threeaddress pairs share the same CoA 483 and MIP signal state 689 entries asa single aggregated message used to manage these bindings, in accordancewith the invention, using the address pair HoA1 at HA1 as the masterbinding. Note that HoA2 485 is listed below HoA1 482 and has no HA fielddefined because it inherits the value from the master binding shown inthe first row of entry 683. In alternative embodiments, the bindingtable can be split so that the address pairs can be searched in thebinding table and the CoA and MIP sig state (which is in a separatetable) is indexed by a pointer associated with the matching addresspair. Where differences exist between the MIP sig state for each addresspair, these can be further indexed out of the binding table by anadditional index to a third table. Essentially though, all embodiments,in accordance with the present invention, share the property of removingredundant information and facilitating the use of aggregated signalingmessages.

[0042]FIG. 8 extends the aggregated signaling and storage concept of thepresent invention to a AAA Request message 860 and a AAA Responsemessage 870 which are passed between an access node 840 and AAA server850, with AAA server 850 including aggregated policy state 855 for theHoAs corresponding to the MN X Network Access Identifier (NAI) 1. Theaggregated policy state includes Profile 875 for a statically allocatedHA1/HoA1 address pair for the MN X. Profile 876 is for a secondstatically allocated HoA2 at the same HA1 as profile 875. Profile 877 isfor a dynamically allocated HoA3 address as a statically allocated HA3address, the AAA server is responsible for the address allocation inthis example but this is for purposes of the example and is not intendedto indicate a loss of generality. The profile 878 is ass ociated with anNAI 2 (Network Access Identifier 2) that is different from the MN X NAI1 associated with profiles 875, 876, 877. Profile 878 is for adynamically allocated HA and HoA from the domain identified in that NAI2. Messages 860, 870 are stored, at least temporarily in memory includedin each of the receiving and transmitting nodes, e.g., as part of thetransmitting and receiving process.

[0043]FIG. 9 is a detailed example of an exemplary request message, anAAA message 860, which can be used as an authentication, authorizationand/or accounting message. The message 860 comprises a MN identifier861, a state request field 862, a first aggregated HA/HoA addressgrouping 869 including HA1 863 and statically allocated HoA1 864, and adynamically allocated address HoA3 865 whose value is not known at thetime of the sending of the request message 860. Both HoA1 and HoA3correspond to the first HA address HA1 863. Therefore elements 863, 864,865 represent two HA, HoA pairs 880, 882. The message 860 furtherincludes a request for a third HA/HoA address pair 884, which includesHA4 866 and HoA4 867, associated with an NAI 2 which is associated withMN X, said NAI 2 is different from said NAI 1. Note that normallyneither HA4 nor HoA4 are known in advance of sending the aggregatedrequest message 860 as they will be dynamically allocated, said dynamicallocation being guided or controlled by the NAI 2 HA4 and HoA4 requests866, 867, and the associated profile state 878. HA/HoA address pairs andrequest form the first part of what can be called an included/excludelist. An include flag 871 is used to indicate that the profiles in theAAA server associated with address pairs 880, 882 and 884 should bereturned to the access node 840, these profiles being profiles 875, 877and 878. The fact that the address pair HA1/HoA2 associated with profile876 is missing from a request with the include flag set indicates thatthe access node 840 does not need the profile 876 to be returned for theMN X. A particular exemplary request message is shown in FIG. 12 wherethe exemplary aggregated request message 860 again includes the MN X NAI1 identity 861 and MIP AAA request state 862. This is followed by anaddress pair 881 comprising HA1 address 868 and HoA2 address 869associated with MN X NAI 1 861 and profile 876. The exclude flag 870 isthen added to the message. This informs the AAA server 850 that the AAArequest is for all profiles and associated allocations that areassociated with MN X that are not mentioned in the AAA request message,these being the same profiles described in FIG. 9. An include flag istherefore generally preferable in a request message when the number ofincluded entries is less than the number of excluded entries. Notehowever that the dynamic allocation of HoA3, HA4 and HoA4 cannot now beguided by parameters in the missing request messages 865, 866 and 867 ofFIG. 12 compared to FIG. 9, and must instead be fully guided by theProfile state 877 and 878. Therefore, a composite of include and excludeentries may be combined in a single message to provide control fordynamic allocation requests with maximum message efficiency. The includeflag 871 and/or exclude flag 870 may be implemented as part of a MIPextension that also implements the list of HA/HoA address pairs, orcould be an MIP header flag, or a specific AAA Attribute Value Pair(AVP) for example.

[0044] Contents of an exemplary AAA response message 870 are shown inFIG. 10 when using either the request message of FIG. 9 or FIG. 12. TheMN X NAI 1 861 and MIP AAA response state 874 are returned to the accessNode 840 along with address pairs 890, 892 and 894. Address pair 890includes HA1 address 863 and HoA1 address 864 along with the associatedprofile 875. Address pair 892 includes HA1 address 863 and dynamicallyallocated HoA3 address 895, and is followed by the associated profile876. Address pair 894 comprises dynamically allocated HA4 address 896and HoA4 address 897 followed by the associated profile 877, addresses896, 897 being allocated from the domain identified by MN X NAI 2.

[0045] In addition to providing message savings, any process at the AAAserver, such as MN authentication, that may typically comprise multiplesteps of messaging and processing that are not shown in FIG. 8, that isnormally conducted for each AAA request message, may, and often is,conducted once for the aggregated message, providing additional benefitsof the invention.

[0046] During a hand-off the MN X profile and associated configurationstate is handed-off between access nodes. This can be performed usingAAA in accordance with the invention. Therefore, an aggregated MIPhand-off message for multiple HoAs of a MN X can trigger an aggregatedmessage to transfer the MN X profile for each HoA to the new accessnode, from the old access node, the old access node effectively becomingthe AAA server 850 of FIG. 8.

[0047] The invention is summarized in an exemplary communications systemof FIG. 11 for the case of an end node 910 which for example is a MobileNode (MN 910), coupled to a first and a second access node 920, 940,respectively, which for example contain MIP v4 Foreign Agents or MIPv6Attendents. Access Nodes 920, 940 may alternately be referred to asForeign Agents (FAs) 920, 940, respectively, since they include FAmodules which allow them to operate as FAs. FAs 920, 940 are bothcoupled to first and second MIP Home Agents or Regional Agents 930, 950(HAs 930, 950). The FA 920 also has a coupling with an Authorization andAuthentication system 905 which enables the FA 920 to authenticate theMN 910 and to obtain an Authorization Profile called the MN Profilewhich is installed into the FA 920 and used to policy the communicationsactivity of the MN 910. All nodes 905, 910, 920, 930, 940, 950 have acommunications routine 907, 911, 921, 931, 941, 951, respectively, usedto send MIP and policy signaling for initial registration and forhand-off of the MN 910 between FAs 920, 940, as well as to forwardpackets between nodes. The nodes 910, 920, 930, 940, 950 have anAggregated MIP Routine 912, 922, 932, 942, 952, respectively, whichenable a single MIP signal, e.g., aggregated message, to affect bindingstate for more that one HoA at a single HA at a time. In addition, nodes910, 920, 940 have an extended routines 912, 922, 942, respectively,which also enable them to use a single MIP message to affect stateassociated with multiple HAs. Routines 912, 922, 932, 942 and 952support and implement aggregation of MIP signaling such that a singleMIP message can be used to manipulate various, e.g., all, MIP state fora MN 910, thereby eliminating the need for a multitude of MIP messagesin order to manipulate the state, e.g., one message for each singleHA/HoA pair as is normally done with conventional MIP signals. Thisenables a binding table 933, 953, 923, 943, 913 and other MIP state inthe HA 930, HA 950, FA 920, FA 940, MN 910, respectively to store stateas if a separate MIP signaling phase was being used for each distinctHoA thereby allowing an aggregated message to be used with aconventional type of binding table. In an alternative embodiment,aggregated binding table state such as the binding table 680 of FIG. 6of the invention can be employed where a single instance of MIPsignaling state associated with a single MN 910 (including MIP flags,security, lifetime, sequences numbers, challenges, tunnel types andother extensions) can be generated for a main Home Agent, Home Addressand CoA triplet. Routines 922, 942 further manage the fan-out, e.g.,de-aggregation, of MIP registration signaling to multiple HAs and thefan-in, e.g., aggregation, from the multiple associated MIP Replies.

[0048] When MN 910 connects to the first FA 920 it sends an aggregatedMIP Registration Request (MIPv4) or Binding Update (MIPv6) message 970 ato the FA 920 including its identity such as at least one Network AccessIdentifier. The FA 920 then sends a message 906 a, such as a RADIUSaccess_request to the AAA system 905 to authenticate the MN 910 andfetch the Policy state 908 for mobility management of Home addressesHoA1, HoA2 and HoA3 at the first and second HAs 930, 950. The HoAs andHAs may be predefined or dynamically allocated but an essentialinventive step is to enable a multitude of Policy state to be returnedto the FA 920 in the Access_Accept message 906 b, triggered by a singleMIP registration message 970 a. If the multiple HoAs are to be allocatedby the HA 930, 950 then they will not be in the returned policy statealthough the policy state for each yet to allocated address may be. Themessage 970 a can include a HA/HoA list extension and associated addresstype information which can be used by the FA 920 to indicate to the AAAsystem which subset of all available policy state is needed for this MN910 at this time. The HA/HoA list can either name each HA domain and theaddress types in each domain, or it can actually include specificstatically allocated HA and HoA identifiers. The named elements can bedesignated as an indication of which policy should, or should not bereturned the FA 920, hence operating as either an INCLUDE or EXCLUDElist. The policy state also should include MIP security associations forsecuring communications between the FA 920 and the HAs 930, 950, betweenthe MN 910 and the FAs 920, 940, and between the FAs 920, 940themselves.

[0049] The policy state is stored in the FA 920 as part of the contextstate for the MN 910 and will normally include at least the address ofeach HA 930, 950 and a place holder for the requested address types fromthat HA. Such address types can be IPv4 public addresses, IPv4 privateaddresses, various IPv6 address types (link, site and global scope, withand without EUI64s) as well as addresses from specific address prefixes(address ranges) that correspond to different commercial entities.Providing multiple addresses from a common address prefix to a MN 910 isuseful if that MN 910 is acting as a Mobile Router and can onwardallocate those addresses. Allocating multiple home addresses to a MN 910from different address prefixes at a HA, e.g., addresses which are notfrom a contiguous block of addresses, is useful because each address canbe owned by different commercial operators with connectivity to that HA,such that each address provides different communications capabilitieswith associated policy constraints to the MN 910. For example, the sameHA can allocate an address from the public ISP of the MN 910 as well asan address from the corporate network of the MN 910.

[0050] Message 970 a for triple HA1 HoA1 CoA, including HA/HoA listextension for, HA1 HoA2 and HA2 HoA3, is converted by routine 922 into apartially aggregated message 970 b including HoA list extension withHoA2 directed to the first HA1 930. The fan-out (deaggregation) processin the FA 920 also sends, in response to receiving an aggregated message970, a deaggregated message 970 c to the second HA 950 for HA2 HoA3 CoA.These messages are used to obtain any dynamically allocated HoAs fromthose HAs which are returned to the FA 920 and the MN 910 in the MIPreply messages. Note that the FA 920 aggregates reply codes and otherinformation from reply messages received in separate reply messages fromthe two HAs for each of the HoAs 1, 2, 3 to enable a single aggregatedReply message to be returned by the FA 920 to the MN 910. These repliescan also include per HA/HoA success failure information which isreturned to the MN 910 intact so that it is fully aware of its evolvingconnectivity and can then attempt to repair any defects with aggregatedor unaggregated signals. T he completion of the MIP registration/bindingupdate signaling results in a single aggregated binding table entry,e.g., aggregated binding table entry 683, being installed in the FA 920and the HA 930 for the HoA 1 and HoA2 which is mapped to the MN 910 andthe Care of Address of the MN 910. Packet flow 960 a from HA 930 to FA920 then includes packets from peer nodes destined for either the HoA 1or HoA 2 of the MN 910, packet flow 960 c from HA 950 to FA 920 thenincludes packets from peer nodes destined to the HoA3 of the MN 910,addresses HoA1,2,3 being assigned to interfaces on the MN 910. If theEnd Node CoA is assigned to another interface on the MN 910 then it is aColocated CoA (CCoA) and packets from the peer nodes will be directedfrom HAs 930, 950 to the CCoA using redirection mechanisms such astunneling or routing headers. If the end node CoA is the FA CoA of FA920, then the HAs 930, 950 instead redirect packets to the FA CoA whichthen forwards them to the MN 910 using the binding information in table680. Therefore packet flow 960 b from FA 920 to MN 910 includes packetsfrom both packet flows 960 a and 960 c.

[0051] As is well known in MIP, the bindings in the HA 930, 950 and FA920 should be refreshed in advance of the binding lifetime expiring.Accordingly, to achieve a high level of aggregation the lifetimes andthe CoAs for the bindings for the MN 910 should all be the same. MIPalso includes a number of other parameters such as tunnel types,challenge and security mechanisms. The more the parameters are commonfor each of the HoAs at each of the HAs, then the greater is theaggregation benefit of the invention. Without loss of generality, thisinvention enables any MIP parameters to be common between the HoAs andthe HAs other than of the course both the HA and HoA addressesthemselves. If the MN 910 wishes to add or drop a specific HoA/HA fromthe aggregate, then the INCLUDE/EXCLUDE list extension (e.g., include orexclude flag) is used to communicate the change to the FA 920 and HAs930, 950 so that the associated policy and MIP state can be amended.

[0052] Further aggregation benefits accrue during hand-off when the MN910 moves to a new FA 940. The case for a reactive hand-off, whereby MIPsignaling is sent via the new FA 940 will be described and is shown inFIG. 9, but an aggregated proactive hand-off whereby the MIP signalingis sent via the old FA 920 and triggers an MIP signal from the old FA920 to the new FA 940 is also possible, in accordance with the presentinvention. The reactive hand-off requires the MN 910 to send anaggregated MIP registration request or Binding Update message 975 a tothe new FA 940, including the HA/HoA list to indicate which packets toredirect to the new FA 940 and which to deprecate. The HA/HoA routine942 will then issue an aggregated Binding Update (BU) message 975 d tothe old FA 920 to update the binding information in the binding table923 in the old FA 920 with the CoA from the prefix of the new FA 940.This newCoA again may be a FA CoA or a CCoA but the modifications willonly be applied to the bindings as indicated by the HA/HoA list in theBU 975 d. Packets destined for the oldCoA in affected bindings are thenredirected to newCoA by the FA 920 to create packet flow 960 d from oldFa 920 to new FA 940 which is onward forwarded to the MN 910 as packetflow 960 e. Unaffected bindings will continue to forward packets to theMN 910 as flow 960 b which will terminate when the HAs 930, 950 stopdirecting packets towards the oldCoA or when the MN 910 decouples fromthe FA 920. The BU message 975 d triggers a message 975 e from the FA920 to the FA 940 which transfers the policy state for the HoAsindicated by message 975 d to enable policy state and MIP configuration,including security state to be transferred to the new FA 940.Undertaking the hand-off in parallel for all HoAs avoids the cost ofmultiple independent MIP hand-off signals which comsumes excessivebandwidth and which independently could fail or become desynchronizedleading to significant complexity. Message 975 a also triggers messages975 b and 975 c to HA 930, 950, respectively, which are aggregated MIPsignals for multiple HoAs at the same HA. These update the bindings 933,953 in the HAs to replace the oldCoA with the newCoA. Packets are thenno longer directed towards the MN 910 via FA 920 and instead go via FA940.

[0053] In summary, significant aggregation benefits can be obtained whena MN has multiple HoAs from a single HA, if the MN has a single HoA frommultiple HAs, and as described in FIG. 9, multiple HoAs from multipleHAs which is the general case. The single MIP signaling phase from MN910 back to MN 910 via FA and HA can be MIP v4 or MIPv6 based, but canreference a multitude of address types associated with HoAs and HAs.Note that a shared CCoA can be used for any combination of IPv4 and IPv6addresses whilst a CoA can only be used for IPv4 addresses of differenttypes.

[0054] The aggregated hand-off signaling can be used afternon-aggregated signaling is initially used to install bindings for eachHoA into each HA, FA. During this initial deaggregated phase, the MN 910can attempt to negotiate maximally uniform parameters across the MIPstate for each HoA so that maximum aggregation benefit is obtainedduring hand-off.

[0055] The provisional applications incorporated by reference into thepresent application include various exemplary embodiments which are notintended to limit the scope of the present application. Any mandatorylanguage such as must, only, necessary, etc, found in the provisionalapplications is intended to be interpreted as applying to the exemplaryembodiments described in the provisional applications and not tolimiting the invention, claims or embodiments described in the presentapplication in any way.

[0056] In various embodiments nodes described herein are implementedusing one or more modules to perform the steps corresponding to one ormore methods of the present invention, for example, signal processing,message generation and/or transmission steps. Thus, in some embodimentsvarious features of the present invention are implemented using modules.Such modules may be implemented using software, hardware or acombination of software and hardware. Many of the above describedmethods or method steps can be implemented using machine executableinstructions, such as software, included in a machine readable mediumsuch as a memory device, e.g., RAM, floppy disk, etc. to control amachine, e.g., general purpose computer with or without additionalhardware, to implement all or portions of the above described methods,e.g., in one or more nodes. Accordingly, among other things, the presentinvention is directed to machine-readable medium including machineexecutable instructions for causing a machine, e.g., processor andassociated hardware, to perform one or more of the steps of theabove-described method(s).

[0057] Numerous additional variations on the methods and apparatus ofthe present invention described above will be apparent to those skilledin the art in view of the above description of the invention. Suchvariations are to be considered within the scope of the invention. Themethods and apparatus of the present invention may be, and in variousembodiments are, used with CDMA, orthogonal frequency divisionmultiplexing (OFDM), and/or various other types of communicationstechniques which may be used to provide wireless communications linksbetween access nodes and mobile nodes. In some embodiments the accessnodes are implemented as base stations which establish communicationslinks with mobile nodes using OFDM and/or CDMA. In various embodimentsthe mobile nodes are implemented as notebook computers, personal dataassistants (PDAs), or other portable devices includingreceiver/transmitter circuits and logic and/or routines, forimplementing the methods of the present invention.

What is claimed:
 1. A communications method comprising the step oftransmitting an aggregated binding message from a first node to a secondnode, said aggregated binding message for registering address bindinginformation, said message comprising: a first address, said firstaddress identifying a node; a second address including a first prefixassigned to the identified node; and a third address being a bindingaddress associated with the second address, said binding address beingfor use in establishing a binding entry mapping said second address tothe third address in at least the identified node; and a fourth addresswith an additional prefix said additional prefix being different fromsaid first prefix, said fourth address establishing an additionalbinding to said third address.
 2. The method of claim 1 wherein saidfirst address is a home agent address, said second address is a firsthome address, said third address is a CoA, and said fourth address is asecond home address, said first, second, third and fourth addresses. 3.The method of claim 1, wherein the additional prefix is allocated to thefirst identified node.
 4. The method of claim 3, wherein the first nodeis one of a mobile end node and an access node and wherein the secondnode is said identified node.
 5. The method of claim 4, furthercomprising: operating said second node to install a single aggregatedbinding table entry between the third address and both of the second andfourth addresses in response to receiving said message.
 6. The method ofclaim 3, wherein the first node is one of an end node and a first accessnode, and the second node is a second access node.
 7. The method ofclaim 6 further comprising: operating said second node to install asingle aggregated binding table entry between the third address and bothof the second and fourth addresses in response to receiving saidmessage.
 8. The method of claim 1 wherein said message further includes:a fifth address assigned to a second identified node, said anotherprefix corresponding to the second identified node, said message furtherestablishing a binding between the third address and the fourth addressin the second identified node.
 9. The method of claim 8, wherein saidfirst node is an end node and said second node is an access node, themethod further comprising: operating said second node to install anaggregated binding table entry establishing a mapping between the thirdaddress and the second address, and also a mapping of the third addressto the fourth address, said aggregated binding table entry furtherincluding said first and fifth addresses, operating said second node totransmit a binding message to each of said first and fifth addresses.10. The method of claim 9, wherein said second node is an access node,the method further comprising: operating said access node to receive anaggregated AAA message from a AAA server, said aggregated AAA messageincluding an end node identifier, MIP state dynamically allocated viasaid AAA server, and a plurality of end node policy profiles, each ofsaid profiles being associated with a different address from a group ofaddresses comprising; said second and fourth addresses.
 11. A memorydevice comprising: an aggregated addresses binding registration messagefor use in a communications system, said aggregated address bindingregistration message including: a plurality of Home Agent Address/HomeAddress pairs associated with an end node; a set of common MIP signalingflags which are the same for each of said plurality of Home AgentAddress/Home Address pairs; and additional Home Agent Address/HomeAddress pair specific signaling information, said pair specificsignaling information including information which is not the same foreach of said plurality of Home Agent Address/Home Address pairs.
 12. Thememory device of claim 11, wherein said pair specific signalinginformation includes at least one MIP signaling flag which is differentfrom the MIP signaling flags included in said set of common MIPsignaling flags.
 13. The memory device of claim 12, wherein said MIPsignaling flags included in said set of common MIP signaling flags arepresent only once in said message.
 14. The memory device of claim 12,wherein said plurality of Home Agent Address/Home Address pairs includea fist Home Agent Address/Home Address pair, and a second Home AgentAddress/Home Address pair, said message including a first Home AgentAddress corresponding to both of said first and second Home AgentAddress/Home Address pairs, said first Home Agent address being presentonly once in said message.
 15. The memory device of claim 14, wherein afirst Home Address corresponds to said first Home Agent Address/HomeAddress pair and wherein said second Home Address corresponds to saidsecond Home Agent Address/Home Address pair, said first and second HomeAddresses being from different non-contiguous blocks of addressesallocated to a Home Agent to which said first Home Agent Addresscorresponds.
 16. The memory device of claim 15, wherein said messagefurther includes a third Home Agent Address/Home Address pair whichincludes a Home Agent Address which corresponds to another Home Agent.17. The memory device of claim 13, wherein said message includes asingle Care of Address corresponding to said end node.
 18. A memorycomprising: an aggregated addresses binding registration message for usein a communications system, said aggregated address binding registrationmessage including a first Home Agent Address corresponding to a firstHome Agent Node, a single Care of Address to be used by said first HomeAgent Node to forward packets being directed to an end node and aplurality of different home addresses assigned to said end node by saidfirst Home Agent node, said plurality of different home addressesincluding at least a first and a second home address, one of said firstand second home addresses being separated from each of the other homeaddresses included in said message by an address value differencegreater than one, such that said one of said first and second homeaddresses is non-contiguous to any other home address in said message.19. The memory of claim 18, wherein said message further includes atleast two different home addresses associated with said first Home AgentAddress, each of said first and second home addresses including adifferent address prefix.
 20. The memory of claim 18, wherein saidmessage includes a single set of MIP signaling flags which areassociated with each of the first and second home addresses, each MIPsignaling flag in said single set of MIP signaling flags being includedin said message only once.
 21. The memory of claim 20, wherein each HomeAgent Address in said message corresponds to one Home Address includedin said message thereby forming a plurality of Home Agent Address/HomeAddress pairs, said message further including first Home AgentAddress/Home Address pair specific signaling state for a first HomeAgent Address/Home Address pair; and second Home Agent Address/HomeAddress pair specific signaling state for a second Home AgentAddress/Home Address pair.
 22. The memory of claim 21, wherein saidfirst Home Agent Address/Home Address pair includes said first HomeAgent Address and said first home address; and wherein said second HomeAgent Address/Home Address pair includes said first Home Agent Addressand said second home address.
 23. The memory of claim 19, wherein saidmessage further includes: a second Home Agent Address and a third homeaddress, said third home address being assigned by said second HomeAgent for use in forwarding packets being directed to said end node. 24.The memory of claim 19, wherein said third home address includes aprefix which is different from prefixes included in said first andsecond home addresses.